A particulate matter sensor or dust sensor may be used to determine a quality of air, for example in a quality of air that is input to and/or output from an air cleaner. In some industrialized regions, environmental air may have high concentrations of particulate matter of different sizes. If the concentration of such particulate matter is high enough, it may be deleterious to human health. Consumers may wish to purchase and install air cleaners for the residences to improve the quality of air breathed in the home. Such consumer grade air cleaners may desirably be modestly priced and compact in size.